Improvement in platform-scales



NITED STATES PATENT OFFICE;

FBANKLIN FAIRBANKS AND LUKE G. SPENGEE, OF ST. JOHNSBUEY, VT., ASSIGNORS TO E. & T. FAIRBANKS 85 CO., OF SAME PLAGE.

MPROVEMENT IN PLATFORM-SCALES.

Specification forning part ofLettcrs Patent No. 213.743, datcd April 1, 1879; application iiled December 21, 1878.

To all whom it may concer:

Be it known that we, FRANKLIN FAIRBANKS and LUKE G. SPENGER, both of St. Johnsbury, Caledonia county, Vermont, (assignors to E. & T. FAIRBANKS &J Co., of same place,) have invented certain new and useful Improvements in PlatfornrScales, of which the following is a specication:

The present improvement applies to that class of large fixed platform-Scales, such as hay, railroad, and other scales, which are exposed to more or less constant vehicle traffic over their platforms; and our invention lies ina novcl relievin g device for lifting the platform otf its pivots, and supporting it firmly in such removed position, so as to relieve the seale nechanism of nnnecessary wear and strain, as hereinat'ter set forth.

In the adjoined drawings, Figure l presents a contracted longitudinal section of a large platform-scale provided with our present invention, the usual lever mechanisn of the scale being omitted for sake of clearness; and Fig. 2 is a cross-section thereof on line x ;20, Fig. 1. Figs. 3 and 4 present end and side elevations, on an enlarged scale, of one of the lifting devices removed.

In small platform-scales, as is well known, itis common to employ what is known as a drop-lover, acting through the medium of the steelyard-rod, to allow the platform,-together with its undcrlying lever mechanism, to drop, so that the platform rests upon edges ofthe platform-casin g, thus relaxin g the in echanism, and relieving it of unnecessary wear or strain during periods of disuse. In large fixed platform-scales, however, where the platform and lever mechanism are so large and heavy, this :mode of relief would be impraeticable; and heretofore no relieving device has been embodied in the structure of this class of scales.

Now, in our invention, we employ a series of lifting devices arranged beneath the plat form, and at or near he corners thereof, as shown in the drawings, which are fixed to the base of the platform-pit, with their upper or actuating ends arranged to bear upwardly against the base of the platform, these several devices being all coupled together, so that by the movement of a lover or equivalent operating device, connecting with the said lifts, and extendin g above the platform, the several lifts are simultaneously moved, so as to raise the platform bodily a suffcient distance off its lever points, and thus relieve the same of all strain, at the same time supporting the platform firmly in such position.

The construction here outlined constitutes the essenee of our invention, which also embodies specific features ofeonstruction, as fully expressed hereinafter.

In Figs. 1 and 2, a a indicate the platformpit sunl en in the ground, as usual, and walled about with masonry, as indicated, and I) b indicate the two main timbers of the platform. The base or under side of these timbers is fit ted at certain intervals with metal piVot-plates or saddles, which rest on the pivots of the system of main levers which extend' transversely across the platform-pit, at corresponding` intervals, in a manner well known to scale-makers, and not necessary to here illustrate.

Now, in the floor of the platformpit, and preferably under each corner of the platform, the lifting devices are arranged as seen in Figs. l and 2, being mounted on two rockshafts, e e, arranged transversely at opposite ends of the platform-pit, as shown. These rocl-shafts are supported at each end in bearings on strong stands or bases d, securely bolted to the timbers or masonry in the floor of the pit, and situated at or near each corner of the platform, as shown. These bases are formed with an upright standard, e, which rises to nearly the base of the platform, as shown. Close to these standards rock-levers fare securely keyed on each end of the rockshafts, while toggle-links g are pivotcd at one end to the rock-levers, close to the fulcrum thereof, and at the other end to platens h h, which are iitted to slide on the top of the standards ce. These platens closely approach the base of the platform-timbers, and present a broad and level surface, as shown, to effectually apply the lifting action of the toggle thereto, while the top of the standard forms a guide for the platen, to retain it in true position and prevent lateral movements thereof.

The rook-shaft at the front end of the scales is provided with an Operating hand-lover, i, which projects through the fioorin g of the scale iito a convenient position in front of the ca v board, as -shownin Figs'. 1 and 2'. Rods k' Te* ment will bring the toggle-links into a vertical v position, and with enormous leverage force the platens at each corner of the scale n'p- Wardly against the platform-timbers, thus litt-g ing the platform bodily oli' its pivots a distance sufficient to relieve the same of all strain or wear, as indicated by dotted lines i Fig. 4.

It will be seen that this' lifting device, while being simple in Construction and action, has such great leverage that the movement tolift or drop' the platform ofi? v or on thepivots isaecomplished with great ease; and, moreover, when the; platform is' lifted, the links assume a straight line with the points of support, and' V formed by the combination of the' rock-leverf,- pivoted to a fixed base, with the link or toggle g g, jointed to the said lever, and arranged to i bear at its' upper end on the baseof thc platform, snbstantially as and for the purpose herein set forth.

thus support the platform firmly as' upon so many solid l egs or pil-lars-, withont any danger of descent, which can be accomplishcdonly by a direct lateral force applied to' the-rocklevers.

In practice, a movement of about one-half incl- 'is imparted to the platens, so that the i 'the actuating ro'ek-leverf, of the toggle-l-in' k g and platenh, arranged* and Operating sub*- stantially as shown and described.-

platform is lifted about one-eighth of aninchclear of the pivots, the=pl`aten`s retiring three"- eighths of an inch below the platform when lowered on= its pivots, as indic'ate'd by the' full and (l'otted li'es in Fig. 4, soas` to' give ample freedom of movement to the' platform under the stress of the weight when the scale'is in" action.

The slot in' tl''e'pla'tform or flooring through I the rock-shatts wand toggles' f g,` fixed'- on the" ends' therefi: and-' arranged toilift tlf'e*platform,` g withthe'connecti-n g-rodslo k,'-cou1`)1ingtogether f the several toggles to' act conjointl y on th'e' p platform, substantiallyasshown anddescribed.

which the operating-lever plays' isprovided with a notch at each end, intowl''ich th'eleve'r sprin'gs when at either end ofits sweep; so* as to prevent any accidentalmovement of the parts when set in either position".

The preciseconstruction shown may be semewhat varied in the details without departing.- 2 from the spirit of our invention; bn't we'have 1 shown the Construction which is' consider-ed` best.

Any snitabfe' Operating device, howe\-'er,

may substitute the hand-lover 'i-fof instance, a hand-wheel on 'an upright shaft-which is geared by bevel or vorm gearing with the rockshaft or by any similar connection. For very long scalc's the liftin'g m'echanism may be made i-n two' or more independent sections or seriesone series, say, to lift one end of the platform, and the other series to lift the opposite end.

What we claim as our' invention is- 1. ln a ,platform -scale, a relieving device consisting of a series of lifts arranged at intervals beneath the platform, fixed to the base' s of the platform-pit, and arrangcd to bear upwardiy at several points upon the platform,

' the said lifts being coupled together and adapted to operate simultaneously by the movement g of a' hand-le'ver or equivalent clevice' projecting above the platform to' ra'i'se theptatform abodi lyofi? its pivots or tolower it thereir,= as g occasion" demands, substantially as her'ein set 2. 'In a platform-s'cal'e, arelievifg device In a platform-scale; the-combinatior,witlf 4. The combina tionyin-aplatform -scalof the `fixed sustaining-standard e withthe' liftingplate'n h, fitted to* slide; on the top* of the said standard, together with: the toggle-link g and roc'k-leverf, substantially as' herein set forth.-

5: The-combinatiom in platform' -sca le',= of

FRANKLIN; FAIRBANKS; nmen: e; sPENeEn.- 

